I have to admit that I laughed a good bit when reading Om Malik's post about "ShadowNumber" last week, which actually turns out to be an alter-ego for VoIP startup TalkPlus. The point appears to be that you can preserve a degree of anonymity through giving out essentially a disposable phone number. It's just interesting to see what companies will do to differentiate themselves. And I completely agree with Om's statement:
Many new technologies — like VHS and DVDs, and more recently Video over the Internet — owe no small part of their early success to adult entertainment, which spurred people to jump through technological hoops they might not have otherwise.
Adult "entertainment" and gaming are two areas that have pushed technology in many areas and yet have not always been credited with doing so.
As to ShadowNumber, their pitch doesn't appeal to me at all (I'm with Om in finding it a bit distasteful), but it's at least something a bit novel. It will be interesting to see if it works out for them.